1. Field of the Invention
The present invention relates to a brake control apparatus for controlling a braking force applied to wheels of a vehicle, and more particularly to the brake control apparatus having a stroke simulating function for providing dummy braking load to a vehicle driver.
2. Description of the Related Arts
An apparatus for providing dummy braking load to a vehicle driver in his braking operation is known as a stroke simulator. For example, German patent publication (Offenlegungsshrift) No. 1961039 discloses an apparatus having the stroke simulating function. In that publication, in order to avoid difficulty in forward movement of the brake pedal in the braking operation, a spring is directly mounted on the brake pedal, and a solenoid valve for use in a braking force control device is controlled to increase or decrease the brake pressure in a wheel brake cylinder of the vehicle in response to the depressing force of the brake pedal, to apply the braking force to each wheel, with the dummy braking load applied to the brake pedal. Also, Japanese Patent Laid-open Publication No. 63-64858 discloses an apparatus which has a solenoid valve disposed between a master cylinder and a wheel brake cylinder mounted on a wheel for selectively changing the communication between the master cylinder and the wheel brake cylinder, and the communication between the master cylinder and an absorbing member for consuming the brake fluid.
According to the one having the spring mounted on the brake pedal as disclosed in the above-identified publication, only a fixed braking load may be provided by the biasing force of the spring mounted on the brake pedal. With respect to the above-described apparatus for controlling the solenoid valve to change the communication between the master cylinder and the wheel brake cylinder, or the communication between the master cylinder and the absorbing member, if the solenoid valve is activated, the master cylinder is communicated with the wheel brake cylinder, so that only a fixed braking load may be provided by means of the absorbing member. Thus, any braking loads corresponding to brake feelings determined on the basis of the vehicle conditions and the driver's taste can not be provided.